Installation Guide

WOOD — Floors, Interior - Ceramic or Porcelain Tile 5
19.2" (488 mm) o.c. joist spacing, single layer OSB
or plywood subfloor
D-W19-T-17
Ceramic or porcelain tile
Unmodified thin-set mortar
DITRA or DITRA-XL
uncoupling membrane
Latex p.c. mortar
Single layer of plywood
or OSB
Joists, I-joists, or
trusses
D-W24-T-17
Ceramic or porcelain tile
Unmodified thin-set mortar
DITRA or DITRA-XL
uncoupling membrane
Latex p.c. mortar
Double layer of plywood
or OSB
I-joists or
trusses
Areas of Application
over any even and structurally sound OSB or
plywood subfloor with 19.2" (488 mm) o.c.
joist spacing
interior dry or wet areas
Limitations
minimum 2" x 2" (50 mm x 50 mm) tile
for natural stone, see detail D-W-S (page 6)
and natural stone discussion (page 26)
Requirements
maximum spacing of joists, I-joists, or floor
trusses is 19.2" (488 mm) o.c.
minimum subfloor thickness – 23/32", 3/4"
nom. (19 mm) tongue-and-groove with 1/8"
(3 mm) gap between sheets
Substrate Preparation
verify that subfloor panels are properly
fastened to framing members
any leveling of the subfloor must be done
prior to installing DITRA and DITRA-XL
Movement Joints
DITRA and DITRA-XL do not eliminate the
need for movement joints, including perimeter
joints, within the tiled surface. Movement
joints must be installed in accordance with
industry standards and norms; see page 17
of this Handbook, TCNA EJ171, and TTMAC
301 MJ
Setting and Grouting Materials
latex portland cement (p.c.) mortar – ANSI
A118.11
unmodified thin-set mortar – ANSI A118.1
grout – ANSI A118.3, A118.6, A118.7,
A118.8
Setting and Grouting Specifications
tile – ANSI A108.5
grout – ANSI A108.6, A108.9, A108.10
Other Considerations
tightly butted and/or tented plywood or OSB
seams must be addressed prior to installing
DITRA and DITRA-XL
vapor barrier on crawl space floors according
to regional building codes
where a waterproof floor is required, all
DITRA and DITRA-XL seams and floor/wall
transitions must be sealed with Schluter
®
-
KERDI-BAND using unmodified thin-set
mortar; see page 12
24" (610 mm) o.c. joist spacing, double layer OSB
or plywood subfloor
Areas of Application
over any even and structurally sound double
layer OSB or plywood floor
Interior dry or wet areas
Limitations
minimum 2" x 2" (50 mm x 50 mm) tile
Requirements
maximum spacing of I-joists or floor trusses
is 24" (610 mm) o.c.
double layer wood floor consisting of:
• minimum subfloor thickness – 23/32",
3/4" nom. (19 mm) tongue-and-groove
• minimum underlayment thickness –
11/32", 3/8" nom. (10 mm)
Substrate Preparation
verify that subfloor panels are properly
fastened to framing members
underlayment – minimum 11/32", 3/8" nom.
(10 mm)-thick Exposure 1, plugged-face
plywood or OSB with 1/8" (3 mm) gap
between sheets; see page 20 for
underlayment installation guidelines
any leveling of the assembly must be done
prior to installing DITRA and DITRA-XL
Movement Joints
DITRA and DITRA-XL do not eliminate the
need for movement joints, including perimeter
joints, within the tiled surface. Movement
joints must be installed in accordance with
industry standards and norms; see page 17
of this Handbook, TCNA EJ171, and TTMAC
301 MJ
Setting and Grouting Materials
latex portland cement (p.c.) mortar – ANSI
A118.11
unmodified thin-set mortar – ANSI A118.1
grout – ANSI A118.3, A118.6, A118.7,
A118.8
Setting and Grouting Specifications
tile – ANSI A108.5
grout – ANSI A108.6, A108.9, A108.10
Other Considerations
tightly butted and/or tented plywood or OSB
seams must be addressed prior to installing
DITRA and DITRA-XL
vapor barrier on crawl space floors according
to regional building codes.
where a waterproof floor is required, all
DITRA and DITRA-XL seams and floor/wall
transitions must be sealed with Schluter
®
-
KERDI-BAND using unmodified thin-set
mortar; see page 12
ceramic or porcelain tile can be installed over
single layer wood subfloors on joists spaced
at 24" (610 mm) o.c. when using DITRA-XL;
see detail D-W24-XL-T on page 6
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